Anyone have experience with...


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Dr. Dickie

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Sep 23, 2020
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341
Finally got the buss bars I wanted, and was getting ready to top balance my EVE 280 Ah cells (8 cells, am doing a 4S 2P). I was torquing down the nuts to 4 Nm (they said they could be torqued to a max of 10 Nm), all were fine, except for one--one stinking positive post.
This EVE set up has the post you screw down into the terminal, then the nut torques down on to the post. One of them would not torque to 4 Nm, it just kept turning. I did not turn it down too much (kind of a relative term), but sure enough the screw down post is just stripping out. Anyone have any experience in what can be done? I got the cells several months ago, and of course no way to prove that I did not over torque them, so if nothing can be done, I will just have to order another cells and wait 4 months to get it in.
Thanks in advance for any suggestions.
 

OffGridInTheCity

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Dr. Dickie

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Sep 23, 2020
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Some ideas to be encouraging - I know you've probably thought of them already.
- Buy a self-tapping screw a little bigger or force a little bigger screw in?
- Buy a cheap screw thread tap set and make slightly wider threads? - https://www.amazon.com/Best-Choice-40-Piece-Tap-Die/dp/B073YC3S8F/ref=sr_1_2
- Solder or Weld something (wire directly or net with threads)?
Thanks OffGridInTheCity
I have taps and dies, not a problem. I amy try that. I also thought, and I probably will try this, just put some JB weld on the screw, screw it in, and let it set. The electrical connection is between the aluminum plate the screw goes into and the buss bar, so the epoxy on the screw should not really affect the connection.
 
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Dr. Dickie

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Sep 23, 2020
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Bummer. The epoxy route did not work :cry:
Time to go the helicoil route. I was really hoping to not have to drill down into the post, but I will report back whether or not it works!
So, there is that.
In hindsight, it is possible this was my fault. I had put the studs in and tightened them down, then put the washer, locking nut, and nut on loosely by hand while I waited for the buss bars I needed to come it--so I would not lose something
When the buss bars came in, I just unscrewed the nuts and took off the washer and locking nut before adding buss bars and torquing them down. It is possible that when I unscrewed the nuts (they were loose and did this by hand) the stud may have not been tight enough and I unscrewed partially out. This would not have left enough threads to hold the stud when torquing. That is "possible," not sure that is what happened, but would explain why all the rest were fine and just this one did not hold.😬
Not thrilled thinking it might be my fault, but I have been known to screw up. Hey, it is how I learn.
 

J_Mack58

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Apr 7, 2021
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145
Bummer. The epoxy route did not work :cry:
Time to go the helicoil route. I was really hoping to not have to drill down into the post, but I will report back whether or not it works!
So, there is that.
In hindsight, it is possible this was my fault. I had put the studs in and tightened them down, then put the washer, locking nut, and nut on loosely by hand while I waited for the buss bars I needed to come it--so I would not lose something
When the buss bars came in, I just unscrewed the nuts and took off the washer and locking nut before adding buss bars and torquing them down. It is possible that when I unscrewed the nuts (they were loose and did this by hand) the stud may have not been tight enough and I unscrewed partially out. This would not have left enough threads to hold the stud when torquing. That is "possible," not sure that is what happened, but would explain why all the rest were fine and just this one did not hold.😬
Not thrilled thinking it might be my fault, but I have been known to screw up. Hey, it is how I learn.
Doc, I looked up that EVE 280 Ah cell and it said it was a M4 screw. So are you going to drill out for a M5 Helicoil?
Amazon has this kit:
https://www.amazon.com/Helicoil-5546-5-Metric-Coarse-Thread/dp/B000BB8XLG

Good luck man, you have to fix it, if you don't you will be tried and found guilty of killing a cell before it's first life. A no-no in the secondlife community. :)
 

Dr. Dickie

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Sep 23, 2020
Messages
341
Doc, I looked up that EVE 280 Ah cell and it said it was a M4 screw. So are you going to drill out for a M5 Helicoil?
Amazon has this kit:
https://www.amazon.com/Helicoil-5546-5-Metric-Coarse-Thread/dp/B000BB8XLG

Good luck man, you have to fix it, if you don't you will be tried and found guilty of killing a cell before it's first life. A no-no in the secondlife community. :)
Thanks
I measured it (I have a string of doohickies that has both screws and nut holes to determine what something is) and I got M6 mm x 1.0, I am going to use that helicore. I have helicores, I hope to have time to do it tomorrow.
 
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Dr. Dickie

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Sep 23, 2020
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Okay, the Helicore worked (so far). That is dang SOFT aluminum on those posts. I think the new EVE cells have gone to a welded post, and I understand why. It makes no sense at all to have a screw in post to thread the nut on, just asking for trouble.
Thanks for all the help everyone. Now to top balance these cells and make the battery, then I am finished with lead acid!
 

J_Mack58

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Joined
Apr 7, 2021
Messages
145
Okay, the Helicore worked (so far). That is dang SOFT aluminum on those posts. I think the new EVE cells have gone to a welded post, and I understand why. It makes no sense at all to have a screw in post to thread the nut on, just asking for trouble.
Thanks for all the help everyone. Now to top balance these cells and make the battery, then I am finished with lead acid!
Hip Hip Horaay!
 
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